As research on the microbiome expands and links are found to many types of diseases, there is still a focus on looking at how the microbiome affects and is affected by disorders of the bowels. Reporting in Nature Microbiology, researchers have observed the microbiome over an extended period of time, determining that people suffering from inflammatory bowel disease are more likely to see huge shifts in composition of their microbiomes compared to healthy individuals. The researchers have termed the phenomenon “volatile dysbiosis.” The following video illustrates the findings.
"We know that there are some key beneficial microbes that are lower in number in people with inflammatory bowel disease. Sometimes the differences are quite substantial," explained the corresponding author of the report, Janet Jansson of the Department of Energy's Pacific Northwest National Laboratory (PNNL). "Our latest results show that patients affected by this condition also have a much less stable gut microbiome than healthy people."
Patients suffering from IBD experience problematic and painful abdominal cramps and diarrhea that results from an attack the immune system launches on microbes in the gut, causing a chronically inflamed state. There are often fluctuations of symptoms in individuals; with it flaring and subsiding in cycles over time. Researchers have found that IBD gut microbiomes tend to have more bacteria that can be pathogenic and irritating, and less of the beneficial kinds of microbes.
"It's important to know not just what microbes are present, but also to understand how the microbial community changes as patients' symptoms improve or worsen over time," said author Colin Brislawn, a PNNL scientist. "We explored the dynamic nature of the disease as it relates to the dynamic nature of the human gut microbiome."
Collaborators on this research followed 137 patients with conditions like Crohn’s disease and ulcerative colitis, and a group of healthy controls over two years. Genetic tools were utilized to assay the microbes present in all of the collected stool samples. The investigators determined that IBD microbiomes have huge swings, with some bacteria disappearing almost completely at times, something rarely seen in controls. Some IBD patients swapped out half of the strains in their microbiome over only a few months. The researchers also saw that medications had a dramatic impact on the composition of the microbiomes.
These findings could help patients by identifying better treatments, such as fecal transplants, or it might help figure out which medications do more harm than good to the microbiome. It could potentially aid in diagnosis of individuals as well.
"The results are an important step in our aim to understand how the microbiome relates to the dynamics of inflammatory bowel disease," said Halfvarson. "Ultimately, manipulation of the microbiome, aiming to mimic the situation and the trajectories of healthy individuals, might become an attractive treatment strategy to maintain IBD patients in remission, especially if immunosuppressants such as corticosteroids can be avoided."